1. Field of the Invention
This invention relates to multifunctional nonionic and partially nonionic siloxane copolymers for binding to and modification of synthetic materials. More particularly, in the present invention the multifunctional nonionic and partially nonionic siloxane copolymers are durably bound to polyamide and polyester materials to simultaneously soften and enhance the hydrophilicity and thermal regulative properties of a fabric made from the synthetic materials. No polymerization between the siloxane copolymer and the synthetic materials takes place in the modification process.
2. Description of the Related Art
Many synthetic materials such as those formulated from polyamide and/or polyester polymers have undesirable hydrophobic character and thermal regulative properties. Thermal regulative properties include such properties as moisture absorption and releasing properties. Past approaches to modify those properties have involved graft polymerization of hydrophilic monomers with the polyamide or polyester polymer, or coating the polyamide or polyester fabrics with an appropriate hydrophilic agent.
Graft polymerization of hydrophilic monomers onto a substrate comprising a polyamide or polyester polymer has been disfavored since such a process can change the molecular structure of the polyamide or polyester polymer dramatically. These changes in molecular structure can result in the loss of desirable physical properties such as fabric strength, thermal regulative properties, and hand. Such graft polymerization techniques are disclosed in U.S. Pat. No. 4,135,877 to Aikawa et al.; U.S. Pat. No. 3,297,786 to Horowitz; U.S. Pat. No. 3,099,631 to Tanner; U.S. Pat. No. 3,252,880 to Magat et al.; and U.S. Pat. No. 3,097,185 to Armen.
Likewise, coating fabrics with hydrophilic agents is not widely accepted because of the poor longevity of the coating when exposed to normal laundering techniques.
Another approach to modify synthetic materials is binding an anionic hydrophilic polysiloxane, to the polyamide or polyester polymer. The binding of the polysiloxane to the polymer is reported to be achieved through both electrostatic and intermolecular hydrogen bonding via anionic groups on the polysiloxane. There is little or no polymerization of the polysiloxane with the polyamide or polyester polymer. The hydrophilicity of the polysiloxane is derived from the anionic binding groups as well as the presence of hydroxyl, alkoxyl and primary hydroxylate groups. See U.S. Pat. Nos. 5,354,815 and 5,408,012 to Barringer, Jr., et al. and Barringer, Jr., respectively.
For the anionic hydrophilic polysiloxanes described in the above-cited Barringer patents, the anionic nature of the binding moieties in the polysiloxane and the electric repulsive nature of the carbonyl groups in the polyester greatly lowers the binding affinity to polyester polymers.
Additionally the hydrophilic alkoxyl groups in the polysiloxane backbone of the Barringer agents, Si--OR groups, can be easily hydrolyzed to reactive Si--OH groups. Neighboring Si--OH groups can then undergo condensation reactions which, in turn, decrease the hydrophilicity and the polysiloxane molecules of the disclosed agents precipitate from the solution before contacting the fabrics to be treated due to the condensation reaction.
The anionic nature of the Barringer agents also prevent the simultaneous treatment of polymer materials with other cationic additives and auxiliaries such as softeners, dispersing agents, wetting surfactants, leveling agents, UV absorbing agents, IR absorbing agents, antistatic agents, anti-foaming agents, fluorescent brightening agents, bacteriostats, fungistats and the like. Moreover, hard water with significant amounts of metal cations must be avoided in the process of treating fabrics with the Barringer agents.
Commonly polysiloxanes provide softening effects and improve hand on the fabrics made of synthetic materials. However, in the Barringer agents most of the functional groups in the polysiloxane backbone are replaced by various anionic acid groups. Consequently, the softening effects of the Barringer agents are reduced to a minimum and an additional softening treatment is required to improve hand after the treatment of the Barringer polysiloxanes.
Thus, it would be a significant advancement in the art to provide a multifunctional nonionic or partially nonionic siloxane copolymer for modification of synthetic materials with binding strength to the synthetic materials. These modified synthetic materials could then be made into a synthetic fabric with more durable enhanced hydrophilicity and thermal regulative properties as well as improved softening effects and hand. Additionally the multifunctional siloxane copolymers could also be used to treat synthetic fabrics directly. The siloxane copolymer can be applied simultaneously with dyeing of the synthetic material or separately.